Verbs - YIN versus YOD

OK, in order to figure out the last part of the first line of zhen pa bzhi bral, we need to learn about the verb is and negations.

As mentioned before, is could have two Tibetan forms, yin and yod. What's the difference?

yin is used when something is:

dkar po kha dok yin - white is a color, remember the object-qualifier-verb rule to figure out what is white and what is color.

yod is used when something exists:

bum pa yod - pots do exist!